Cellular, or porous, materials have the ability to absorb significantly more energy than solid structures because of their ability for densification in response to impacts. As such, cellular materials such as metallic or ceramic foams have been proposed as an energy absorbing layer in armor-type systems; however, the random microstructure of these materials severely diminishes their mechanical properties. The deformation of a cellular foam is dominated by the bending behavior of the cell struts. Simple mechanics dictates that bending dominated structures are less efficient in load carrying capacity than compression dominated behavior exemplified by a truss structure.
U.S. Pat. Nos. 6,698,331 and 7,128,963, which are incorporated by reference herein in their entirety, propose blast protection material systems that incorporate random cellular ceramic or metallic foam as an energy absorbing layer. However, these patent disclosures do not provide an ordered micro-truss structure. The use of metallic lattice (truss) materials for energy absorbing application is discussed in U.S. Pat. No. 7,382,959 and U.S. patent application Ser. Nos. 11/801,908 (now U.S. Pat. No. 8,197,930); 12/008,479 (now U.S. Pat. No. 8,320,727); 12/074,727 (now U.S. Pat. No. 7,687,132) and 12/075,033 (now U.S. Pat. No. 7,653,276), which are incorporated by reference herein in their entirety. However, there is still a need to provide an impact or blast energy absorbing material able to support a load, be lightweight, structurally stiff and allow controlled, predictable failure points. The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person skilled in the art